Emission and level population in noble gases and their binary mixtures under ion beam excitation

The luminescence spectra for noble gases and their binary mixtures excited by Ar ions with energies up to 70 MeV were examined in the range of 200–980 nm. The emissions at the transitions of heteronuclear ionic molecules ArXe⁺, ArKr⁺, KrXe⁺ were studied for a gas-mixture, with a wide variation in the percentage composition. The noble gases atomic spectra are dominated by lines of (n + 1)p-(n + 1)s-transitions (2p-1s in Pashen's notation); lines of d-(n + 1)p-transitions were also observed. The distribution of radiation over 2p-levels of noble gas atoms was also measured. The sharp predominance of the fraction of radiation from the levels 2p₂ of Ar, 2p₆ of Kr and 2p₅ of Xe is partially explained by the relatively small values of the rate constants for the deactivation of these levels, by own atoms. The mechanisms of levels population under the excitation of noble gases by ionizing radiation are discussed.